The purpose of this study is to determine whether adaptive servo-ventilation (ASV) or continuous positive airway pressure (CPAP) is better at treating complex sleep apnea over time.

Between 3 and 19% of patients with clinical and polysomnographic features of obstructive sleep apnea syndrome (OSA) develop a high-frequency of central apneas and/or disruptive Cheyne-Stokes respiratory syndrome after application of continuous positive airway pressure (CPAP), a pattern called the complex sleep apnea syndrome (CompSAS). The trial seeks to determine the efficacy of the ASV vs. CPAP modes for the treatment of CompSAS over time. Baseline clinical and laboratory data will be collected, patients will be randomized to one of the two treatments. Overall study participation is approximately 3 months.

Inclusion Criteria:

• Diagnosis of complex sleep apnea syndrome (CompSAS)
• Naive to PAP therapy
• Requires CPAP ≤15 cm H2O

Exclusion Criteria:

• Requires supplemental oxygen or with a baseline SaO2 <90%
• Requires CPAP > 15 cm H2O
• Primary diagnosis of moderate to severe chronic obstructive pulmonary disease, neuromuscular disease, chronic hyperventilation, stroke, cognitive impairment, such that could impair ability to answer subjective questions (study questionnaires) or unstable heart failure
• Any contraindication for nasal or oro-nasal positive airway pressure, such as claustrophobia, severe nasal obstruction, or impaired mental status